Enhanced photocatalytic hydrogen production over Co3O4@g-C3N4 p-n junction adhering on one-dimensional carbon fiber

Abstract

Photocatalytic hydrogen production from water using photocatalysts is a desirable method to produce renewable energy. Specifically, combining multiple semiconductors to separate charges effectively is an achievable way to improve photocatalytic hydrogen production. In this study, a novel photocatalyst which tricobalt tetraoxide (Co3O4) modified graphitic carbon nitride (g-C3N4) nanosheets and at the same time their adhered to one-dimensional carbon fibers (CNFs) carrier (denoted as Co3O4@g-C3N4/CNFs) was successfully prepared. The single CNFs was obtained by electrospinning technique and high temperature calcination. The g-C3N4/CNFs was fabricated through the vapor deposition method. After that, the Co3O4@g-C3N4/CNFs photocatalyst was successfully composed with the hydrothermal treatment of cobalt chloride hexahydrate and roasting technology under air condition. In addition, the photoactivity of the catalysts was evaluated by hydrogen production from photocatalytic water splitting, and the result showed that the hydrogen evolution rate was in the following order: Co3O4@g-C3N4/CNFs composite > g-C3N4/CNFs. The composite of Co3O4@g-C3N4/CNFs exhibited a hydrogen production rate of 67.17 μmol g−1 h−1, while the rate for hydrogen production of g-C3N4/CNFs was 49.67 μmol g−1 h−1. It was known that the Co3O4 particles which were uniformly dispersed on the surface of g-C3N4/CNFs efficiently enhanced separation photo-generated electron-hole pairs, thus improving the visible-light photocatalytic activity.